Electrical connectors



June 7, 1966 c. F. ROBB INS 3,255,428

ELECTRICAL CONNECTORS Filed Nov. 16, 1964 2 Sheets-Sheet lz/ll'l'I/lY/[L III I June 7, 1966 c. F. ROBBINS 3,255,428

ELECTRICAL CONNECTORS Filed Nov. 16, 1964 2 Sheets-Sheet 2 3,255,428ELECTRICAL CONNECTORS Clyde F. Robbins, Milwaukee, Wis., assignortoCutler- Hammer, Inc., Milwaukee, Wis., a corporation of Dela- WareFiled Nov. 16, 1964, Ser. No. 411,212 8 Claims. (Cl. 339-95) Thisinvention relates to electrical connectors and more particularly toquick-connect connectors of the plug-in terminal type.

While not limited thereto, the invention is especially applicable toconnection of conductors or wires to miniature electrical devices suchas switches, relays and the like where the space for the connector islimited and a strong connection is required.

An object of the invention is to provide improved electrical connectors.

' A more specific object of the invention is to provide double-gripconnectors of the plug-in terminal type.

Another specific object of the invention is to provide improvedquickly-connectable electrical connectors of small size having superiormechanical characteristics.

Another specific object of the invention is to provide improvedquickly-detachable electrical connectors of small size having superiorelectrical and mechanical characteristics.

A further specific object of the invention is to provide improvedelectrical connectors of small physical size particularly in verticaldimension which are economical to produce and easy to assemble.

Other objects and advantages of the invention will hereinafter appear.

These and other objects and advantages of the invention and the mannerof obtaining them will best beunderstood by reference to the followingdescription of embodiments thereof taken in conjunction with theaccompanying drawings, wherein:

FIGURE 1 is a cross-sectional view of an electrical connectorconstructed in accordance with the invention;

FIG. 2 is an isometric view of the connector spring clip of FIG. 1;

FIG. 3 is a cross-sectional view like FIG. 1 but showing a relativelylarge diameter conductor inserted in the connector;

FIG. 4 is a cross-sectional view taken along line 44 of FIG. 3;

FIG. 5 is a cross-sectional view like FIG. 3 showing the double-gripaction when the conductor is pulled;

FIG. 6 is an isometric view of a portion of the pocket in which theconnector is retained;

FIG. 7 is a cross-sectional view like FIG. 1 but showing a relativelysmall diameter conductor inserted in the connector;

FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7;

FIG. 9 is a cross-sectional view like FIG. 7 showing the double-gripaction when the conductor is pulled;

FIG. 10 is an isometric view of a modified connector spring clip;

FIG. 11 is a cross-sectional view of a connector having the modifiedspring clip of FIG. 10 and showing an intermediate size conductorinserted therein; and

FIG. 12 is a cross-sectional view taken along line 12 12 of FIG. 11.

Referring to FIGS. 1-6, there is shown in accordance with the inventionan electrical connector of the plug-in terminal type mounted in theinsulating housing 2- of an electrical switch or the like. Housing 2 isshown as being comprised of a base 2a and a cover 2b. Base is providedwith a small pocket or cavity 4 opening at the top and having agenerally rectangular shape in 3,255,428 Patented June 7, 1966 flatbottoms whereas the intermediateportion may incline at an angle of about45 degrees or more from the horizontal.

As shown in FIG. 6, the raised or shallower portion 4c of the cavity isconstricted so that its width is only.

one-half or less than one-half the width of the deeper portion 4a of thecavity and is alined with one side of the deeper portion. The cornerbetween the wider portion and the narrower portion of the cavity isprovided with a bevel 4d. This angular wall provided by the bevel 4d isengaged by the end of a wire pushed into the cavity to cam the wire toone side of the cavity.

A hole 6 extends from the upper part of the deeper end of cavity 4through the wall of the base. As shown in FIG. 4, hole 6 is tapered incross-section to allow insertion of a wire through the wider part and toallow insertion of a release tool through the narrower part of the hole.

An electrical terminal 8 extends along the upper surface of base 2a tooverlie cavity 4. As shown in FIGS. 4 and 6, terminal 8 may be fiat andthe opposite upper corners of the walls of cavity 4 may be recessed at4e to accommodate a terminal 8 slightly wider than the cavity to fix theterminal over the cavity. This terminal covers the cavity and aninsulating cover plate 2b lies over terminal 8 and hole 6. While thehousing has been shown as comprised of a base and a cover, it will beapparent that other forms are possible; for example, the part of cover2b overlying hole 6 could be molded integrally with the base and theremainder of the cover omitted. In such version, terminal 8 alone wouldcover the cavity and hole 6 would open only at its opposite ends and notat the top.

A connector spring clip 10 of the double-grip type rests in the deeperportion 4a of the cavity. Clip 10* is provided with a substantiallyU-shaped configuration and comprises a short strip of thin spring metalbent back roundedly upon itself at the center. As shown in FIG. 1, leg10a of clip 10 may be slightly shorter than the other leg 10b. Clip 10is dropped in the deeper portion of cavity 4 yoke portion first so thatterminal 8, when placed in position, engages and slightly flexes leg 10aof the clip to hold it at a slant as shown in FIG. 1 and to keep it fromrattling in the pocket.

As shown in FIGS. 1 and 6, raised portion 40 of the cavity which isnarrower than the remainder of the cavity and otfset to one side thereofprovides shoulder 4 one on side wall continuing in the direction ofincline 4b for some distance and then terminating in a vertical wall 4g.Leg 10b of the clip rests on this shoulder and is retained thereby sothat the other leg can be flexed sufiiciently to hold the connector clipimmobile within the cavity and to keep it from rattling therein.

Connector clip 10 is arranged to grip the end portion of an electricalwire 12 from which the insulation has been removed. As shown in FIG. 3,hole 6 is large enough to receive a portion of the insulated part of thewire whereas the bare part of the wire flexes leg 10a as it is forcedbetween terminal 8 and the clip and pushed all the way into the narrowend of the cavity. The bare wire passes freely over and past leg 10b ofclip 10. When so inserted, the bare wire slides along terminal 8 and isheld in good electrical contact therewith by the clip.

As shown in FIG. 4, wire 12 is inserted into the cavity through thelarger side of hole 6. The smaller side of hole 6 remains open so that atool such as a pin may be inserted to pry leg a away from the wire torelease the latter for removal.

As shown in FIG. 5, connector spring clip 10 affords double-gripfunction if the wire is pulled. When the wire 12 is pulled in thedirection of the arrow, it will be restrained by leg 10a of the clipbiting into the wire and clamping the wire against terminal 8. A strongpull will cause the clip to flex elastically, slide and rotate in thedee er portion of the cavity so as to force up the other leg 10!) intobiting engagement with the wire for positive gripping. Both legs of theclip now restrain the wire to prevent it from being pulled completelyout. When the wire is released, the clip restores and moves the wireback to the position shown in FIG. 3.

FIGS, 7, 8 and 9 show how the same connector spring clip can be used forconnecting a relatively thin wire 14- to terminal 8. The wire may beeither a solid wire or a stranded wire which has been tinned or dippedin solder to stiffen it. Since the upper leg 10a of clip 10 is longenough to be slightly flexed by terminal 8 before a wire is inserted,the clip is capable of engaging and retaining even a thin wire as shownin FIGS. 7 and 8. When this wire is pulled, the clip elastically flexesand rolls or slides in the cavity to bring up the other leg also intobiting engagement with wire 14.

While leg 10a of the connector spring clip has been shown in FIGS. 19 asbeing slightly shorter than the other leg 10b, it will be apparent thatthe relative lengths of the two legs may depend on the range of wiresizes that it is desired to connect. For example, if only small wire isto be connected, leg 10b could be longer than that shown in FIG. 7. Arequirement is that leg 10]) should have a length allowing the wire topass thereover to the rear end of the narrower portion of the pocketwhen it is inserted. Leg 10b must be long enough so that it will cOrneup and grip the wire when the wire is pulled. Leg 16a is preferably longenough so that it will be engaged or slightly flexed by the terminal tokeep the clip from rolling in the pocket before the wire is insertedthereinto.

FIGS. 1012 show a modified connector spring clip 16 for holding aconductor 18 against a modified terminal 20. As shown in the isometricview in FIG. 10, clip 16 differs from that hereinbefore described inthat the ends of the two legs thereof are cut at a small angle. Bothlegs are preferably provided with the same angle in the same direction.These angular ends of the clip tend to force the wire to one side of thecavity. As shown in FIGS. 11 and 12, terminal 20 is Wider and has adownwardly bent edge 20a fitting into a deeper notch in one upper cornerof the wall of the cavity on the side corresponding to the larger sideof hole 6. The angular end on leg 16a of the clip tends to move wire 18into the 90 degree corner between terminal 20 and its bent edge 20a toafford a large area electrical contact between the wire and theterminal.

While the ends of the U-shaped connector spring clip have beenillustrated as being cut straight across in FIGS. 1-9 and as being cutat an angle in FIGS. 1012, it will be apparent that other forms arepossible. For example, the ends of the spring clip could be providedwith V- notches at various angles or could be pointed, that is, aninverted V, at various angles. These slanted or pointed ends tend tokeep idle clips from rattling. A preferred form may be a flat terminalplate as shown in FIGS. l-S in combination with a U-shaped connectorspring having slightly angled ends on its legs as shown in FIGS. 1012.Also, when two connectors for a pair of wires are used in a switch base,the angles on the legs of the two springs are arranged in oppositedirections to force the two wires as far apart as possible in a two-poleswitch. This requires left-hand and right-hand springs. An alternativewould be pointed ends on the legs of the connector spring in combinationwith the narrow portion in the cavity as a molded guide for the wire. Alike pointed leg spring could be used for both poles of a two poleswitch to 'force the wires far apart.

While the invention hereinbefore described is effectively adapted tofulfill the objects stated, it is to be understood that I do not intendto confine my invention to the particular preferred embodiments ofelectrical connectors disclosed, inasmuch as they are susceptible ofvarious modifications without departing from the scope of the appendedclaims.

I claim:

1. A releasable double-grip electrical connector comprising:

an insulating housing having a pocket therein open at the top;

said pocket comprising an inclined wall and being free of anyimpediments to enable dropping of a connector clip thereinto through itsopen top;

a connector clip comprising a U-shaped strap of spring material freelyresting in said pocket with a first leg thereof extending at an upwardangle in the pocket and with the second leg thereof lying on saidinclined wall;

an electrical terminal member overlying said pocket;

a hole in the wall of the housing opposite said inclined wall forreceiving the bare wire end portion of an insulated conductor;

said first leg of said connector clip having a length relative to theheight of the pocket such that insertion of said wire through said holecauses flexing thereof and pressing of said bare wire against saidterminal member as said bare wire passes freely over the end of saidsecond leg of said clip;

and the lower bent portion of said clip being rounded sufficiently tohug the walls of said pocket and said second leg of said clip having alength relative to the height of said pocket such that pulling on saidconductor causes said first leg to elastically flex while it remains inbiting engagement with said bare wire and causes the bent portion ofsaid clip to flex elastically and slide and rotate in said pocket toforce the end of said second leg into biting engagement with said barewire whereby both legs of said clip grip said bare wire in a directionrestraining removal thereof from contact with said terminal.

2. The invention defined in claim 1, wherein:

the legs of said connector clip are provided with straight-across cutends so that they are at a right angle wit-h the edges thereof.

3. The invention defined in claim 1, wherein:

the legs of said connector clip are provided with angular ends slantingat a small angle from one edge of said connector clip to the other edgethereof.

4. The invention defined in claim 1, wherein:

said pocket is extended through substantially a half of the upperportion of said inclined wall to provide room for insertion of the bareWire beyond said second leg of said connector clip, the remainder of theupper portion of said inclined wall providing a rest for the end of saidsecond. leg of said connector clip.

5. The invention defined in claim 1, wherein:

said electrical terminal member comprises a flat plate having adown-turned edge portion forming a right angle at one upper corner ofsaid pocket providing larger contact area for the bare wire.

6. The invention defined in claim 1, wherein:

said hole in the housing wall opposite said inclined wall is providedwith an elongated cross-sectional shape to provide space alongside thebare, wire for insertion of a release tool.

7. The invention defined in claim 1, wherein:

said first leg of said connector clip is provided with a lengthsufficient to cause it to be slightly flexed by said terminal memberbefore the bare wire is 5 inserted thereby maintaining said second legin contact with said inclined wall and said bent portion thereof incontact with said opposite wall of said pocket. 8. The invention definedin claim 1, together with: an insulating cover overlying said terminalmember to close said pocket; and the arrangement being such that theconnector can be assembled -by'dropping the connector clip in thepocket, placing the terminal member over the pocket and securing theinsulating cover to close the top of the pocket.

References Cited by the Examiner UNITED STATES PATENTS 6 2,738,4823/1956 Benander 33995 X 2,993,190 7/1961 Sams et al. 33995 X 3,138,4216/1964 Locher et a1 339-95 References Cited by the Applicant UNITEDSTATES PATENTS 1,950,826 3/1934 Smart. 2,705,785 4/1955 Benander.2,780,791 2/ 1957 Morschel. 2,883,641 4/ 1959 Despard. 2,913,698 11/1959Bromley.

FOREIGN PATENTS 838,778 7/1952 Germany.

JOSEPH D. SEERS, Primary Examiner.

W. D. MILLER, Assistant Examiner.

1. A RELEASABLE DOUBLE-GRIP ELECTRICAL CONNECTOR COMPRISING: ANINSULATING HOUSING HAVING A POCKET THEREIN OPEN AT THE TOP; SAID POCKETCOMPRISING AN INCLINED WALL AND BEING FREE OF ANY IMPEDIMENTS TO ENABLEDROPPING OF A CONNECTOR CLIP THEREINTO THROUGH ITS OPEN TOP; A CONNECTORCLIP COMPRISING A U-SHAPED STRAP OF SPRING MATERIAL FREELY RESTING INSAID POCKET WITH A FIRST LEG THEREOF EXTENDING AT AN UPWARD ANGLE IN THEPOCKET AND WITH THE SECOND LEG THEREOF LYING ON SAID INCLINED WALL; ANELECTRICAL TERMINAL MEMBER OVERLYING SAID POCKET; A HOLE IN THE WALL OFTHE HOUSING OPPOSITE SAID INCLINED WALL FOR RECEIVING THE BARE WIRE ENDPORTION OF AN INSULATED CONDUCTOR; SAID FIRST LEG OF SAID CONNECTOR CLIPHAVING A LENGTH RELATIVE TO THE LENGTH OF THE POCKET SUCH THAT INSERTIONOF SAID WIRE THROUGH SAID HOLE CAUSES FLEXING THEREOF AND PRESSING OFSAID BARE WIRE AGAINST SAID TERMINAL MEMBER AS SAID BARE WIRE PASSESFREELY OVER THE END OF SAID SECOND LEG OF SAID CLIP; AND THE LOWER BENTPORTION OF SAID CLIP BEING ROUNDED SUFFICIENTLY TO HUG THE WALLS OF SAIDPOCKET AND SAID SECOND LEG OF SAID CLIP HAVING A LENGTH RELATIVE TO THEHEIGHT OF SAID POCKET SUCH THAT PULLING ON SAID CONDUCTOR CAUSES SAIDFIRST LEG TO ELASTICALLY FLEX WHILE IT REMAINS IN BITING ENGAGEMENT WITHSAID BARE WIRE AND CAUSES THE BENT PORTION OF SAID CLIP TO FLEXELASTICALLY AND SLIDE AND ROTATE IN SAID POCKET TO FORCE THE END OF SAIDSECOND LEG INTO BITING ENGAGEMENT WITH SAID BARE WIRE WHEREBY BOTH LEGSOF SAID CLIP GRIP SAID BARE WIRE IN A DIRECTION RESTRAINING REMOVALTHEREOF FROM CONTACT WITH SAID TERMINAL.